/**
 * 添加水印
 */
let watermark = {}

let setWatermark = (str, el, id) => {
  let parentDiv = el || document.body
  console.log(typeof document.getElementById(id))
  if (document.getElementById(id) !== null) {
    try {
      parentDiv.removeChild(document.getElementById(id))
    } catch (e) {}
  }
  // 创建一个画布
  let can = document.createElement('canvas')
  // 设置画布的长宽
  can.width = document.body.clientWidth
  can.height = document.body.clientHeight
  // can.width = document.body.clientWidth / 3
  // can.height = document.body.clientHeight / 3
  let cans = can.getContext('2d')
  // 旋转角度
  // cans.rotate((-15 * Math.PI) / 180)
  // cans.border = '20px green solid'
  cans.font = can.width / 18 + 'px Vedana'
  // cans.font = '300px Vedana'
  // 设置填充绘画的颜色、渐变或者模式
  cans.fillStyle = 'rgba(99, 99, 99, 0.15)'
  // 设置文本内容的当前对齐方式
  cans.textAlign = 'center'
  // 设置在绘制文本时使用的当前文本基线
  cans.textBaseline = 'Middle'
  // 在画布上绘制填色的文本（输出的文本，开始绘制文本的X坐标位置，开始绘制文本的Y坐标位置）
  cans.fillText(str, can.width / 2, can.height / 1.92)

  let tempHeight = can.height - 30
  cans.beginPath()
  cans.moveTo(0, tempHeight)
  cans.lineTo(can.width, 0)
  cans.strokeStyle = cans.fillStyle
  cans.stroke()

  cans.beginPath()
  cans.moveTo(0, 0)
  cans.lineTo(can.width, tempHeight)
  cans.strokeStyle = cans.fillStyle
  cans.stroke()

  cans.beginPath()
  cans.moveTo(can.width / 2, 0)
  cans.lineTo(can.width / 2, tempHeight)
  cans.strokeStyle = cans.fillStyle
  cans.stroke()

  cans.beginPath()
  cans.moveTo(0, tempHeight / 2)
  cans.lineTo(can.width, tempHeight / 2)
  cans.strokeStyle = cans.fillStyle
  cans.stroke()

  let div = document.createElement('div')
  div.id = id
  div.style.pointerEvents = 'none'
  div.style.top = '0px'
  div.style.left = '0px'
  div.style.position = 'absolute'
  div.style.zIndex = '100000'
  // div.style.border = '10px red solid'
  div.style.width = '100%'
  div.style.height = '100%'
  div.style.background = 'url(' + can.toDataURL('image/png') + ')'
  // div.style.backgroundSize = 'cover'
  parentDiv.appendChild(div)
  return id
}

// 该方法只允许调用一次
watermark.set = (str, el, id1) => {
  let id = setWatermark(str, el, id1)
  setInterval(() => {
    if (document.getElementById(id) === null) {
      id = setWatermark(str, el, id)
    }
  }, 500)
  window.onresize = () => {
    setWatermark(str, el, id)
  }
}

export default watermark
